Abstract: The massive microbial reef composed of Cyanobacteria of upper Xiaoerblak formation of the Lower Cambrian found in Sugaite?blak area in Tarim basin is distributed in NNE?SSW, with thickness of 30~70 m and two?stage progradation features. The first stage is characterized by autochthonous growing Epiphyton, the second one by thrombolites and stromatolites. The interior structures of the microbial reef show that the evolutions of grain bank→autochthonous growing Epiphyton reef→thrombolites→stromatolites from the bottom to the top indicate that the growth of the microbial reef is a gradually increasing process of hydrodynamic intensity upward